The move is part of the Obama administration’s continued effort to ratchet up pressure on the Assad regime.

“With regard to Ali Abdul Karim Ali, our concern was the close ties that he's maintained with Syrian intelligence throughout his diplomatic career. With regard to Walid al-Moallem, he's continued to beat this drum of international conspiracy and has -- and has attempted to cover up the regime's horrific activities by making claims that terrorists or others were responsible. And Bouthaina Shaaban has served as the public mouthpiece for the repression of the regime,” U.S. State Department spokesperson Victoria Nuland told reporters.

Regarding the ambassador to Lebanon, she added, "We believe that his activities in Lebanon were not compatible with his diplomatic status… we have been concerned -- and we've conveyed these concerns to the Lebanese government -- about harassment of Syrians in Lebanon and the disappearance of some of them.”

Nuland said U.S. Ambassador to Syria Robert Ford has met with the foreign minister, most recently in the past couple weeks, and these sanctions don’t preclude them meeting again. The sanctions also don’t prevent the foreign minister from attending next month’s U.N. General Assembly meeting in New York, since the U.S. is treaty-bound to allow individuals to attend.